1. Field of the Invention
The present invention relates to racking assemblies for avionic equipment, and more particularly to electrical connectors associated with such racking assemblies.
2. Brief Description of the Prior Art
Modern aircraft require that the avionics system be broken down into subcomponents thereof with these subcomponents housed in modules which can be easily removed from the avionics system and replaced with identical subcomponents. This is required beause the repair of an electronics module can be quite a complex job and can take some time, and the aircraft cannot be allowed to stay idle for the length of time normally necessary to repair the malfunction. When the avionics system malfunctions, it is the common practice to isolate the malfunction down to the module level, remove the malfunctioning module for offsight repair, and replace it immediately with a good module. This allows for a fast turnaround time for the aircraft.
These electronics modules are usually housed in a metal case which can be slideably inserted into a rack and panel assembly or tray located in the avionics bay of an aircraft. Plug-in type electrical connectors are conventionally located on the rear of the module's casing to plug the electronics of the module into the electronics of the avionics system.
With the advent of integrated circuitry and with the increasing complexity and sophistication of avionics systems, these avionics modules are increasingly filled with ever more circuits, requiring a similar increase in the number of electrical interconnections between the module and the tray. These electrical interconnections are conventionally accomplished by means of male plugs which insert into sockets. As each plug/socket combination must mate firmly, there is an inherent resistance to mating. As the total number of plug/socket combinbinations has increased, the cumulative force of resistance to mating of the avionics modules has become quite large.
A conventional rack and panel or tray plug connector, as called for by Aeronautical Radio, Inc. (ARINC) standard 404, has a connector shell bracket in which are mounted two projecting hollow male shells. The male shells house an insulating material in which are mounted a plurality of sockets for reception of the plugs of a corresponding plug connector mounted on the rear of the avionics module. This latter plug connector has a bracket with a pair of recesses for reception of the two male shells. The brackets of the plug connectors are mounted over openings in the rear of the avionics module and the backplate for the avionics tray.
When the avionics module is first inserted into the tray, the male shells of one connector align with the female recesses of the other connector. All the plug/socket pairs also align. When the avionics module is pushed further into the tray, the plug/socket combinations resist mating. A considerable force must be exerted on the avionics module the overcome this resistance. In practice, this force is great enough to cause the tray mounted bracket to bow backwards along a line between the two male shells. This bowing causes the plug/socket pairs to become misaligned. This misalignment further increases the resistance to insertion. If further force is applied to the avionics module, a point will be reached where the bowing is so great that further insertion becomes impossible. In this condition, the avionics module is jambed.
Bowing of the connector bracket results in misalignment of the plug/socket pairs. As a result of an insertion force being applied during such misalignment the plug/socket pairs may become damaged or otherwise separated. This can cause an avionics malfunction due to an open circuit.
The bowing may cause some of the plug/socket pairs to barely mate. During aircraft vibration or shock, certain plug/socket pairs may become temporarily separated causing an intermittent and very difficult to locate avionics malfunction.